Bore scoping a barrel

3

338lm

Guest
For those who bore scope your barrels:
When you start shooting a new barrel does the throat area start to discolor the steel from the high temperatures? Or is this powder buildup still left in the barrel after cleaning?
I notice when I scope my new barrels as I shoot them that I have darkened steel in the throat area (first few inches). I tend to see more of it in the grooves than on the lands. It does not look like powder buildup, it looks more like the steel is discoloring. Want to know if this is typical or if it is because of my cleaning method. I use good quality bronze brushes.
 
If you can get the discoloration off with leaning it is powder residue, if not it is the barrel starting to erode from use. There is a cross-pattern roughness that begins to appear with barrel erosion. With something like a 6PPC it will start to appear at about 300-500 rounds depending on the barrel and how hot you are loading it.

One thing, if you are using a Hawkeye, it has a warm copper colored glow from the bulb that comes with it. There is another bulb available that will make the light more blue and brighter.
 
Thanks Guys. I wrapped a bronze brush with a patch, and saturated the patch with bore paste. Cleaned every bit of the black out of the barrel.
Barrel looks like new.
 
I use a nylon brush wrapped with a patch, and JB Bore-Brite, to remove the powder fouling in the throat. The way I am able to tell when its time to use the bore paste is when a solvent soaked patch becomes difficult to start in the bore. Normally it goes in easily when the carbon ring is gone.
Another thing to check just out of curiosity, is now that it is clean, chamber a dummy round with the bullet seated long to find the measurement to the lands. Then, before you clean it again, recheck this depth with another round. After 50 shots my .223 will change .020. This can play havoc with your rifle if it is tuned to a specific distance from the lands. That is why I now tuned my rifle to shoot with .001 neck tension and .005 jam. If the fouling buildup pushes the bullet in a little more, it doesnt shoot totally different.
Before you recheck the seating depth, clean as normal with your brush and solvents so that you are only measuring how much the carbon ring is changing the depth.
I use a nylon brush because I cant reverse a bronze brush in the bore with a patch on it.
 
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I have seen

a couple of barrels that showed just one black grove. I assumed that the barrel was shot out because of this but might this mean that the BLACK grove may be deeper than the others and too deep for a brush or patch to reach the carbon? One barrel I had in the past had one grove that was black most of the length of it.
 
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The discoloration that I could see looked like a bad bluing job on the first 8 inches or so of the barrel in all the grooves. It is very shiny and looks like faint bluing. Im not sure what it would mean if only one groove was discolored as I havent seen that condition in any of my rifles.
 
You may like....

..to try Chevron's "Techrylene" (sp) made for carbon cleaning before using any type of bore paste.
 
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